Resin piping assembly, and process of forming the same

ABSTRACT

A resin piping assembly including a base divisional component having first and second half components having respective first and second interfacial surfaces formed along an oil passage, and first and second divisional components which have respective third and fourth interfacial surfaces formed along the oil passage, and which are bonded to the respective first and second half components. Each of the base divisional component, and the first and second divisional components is formed of a resin material, and the first and second interfacial surfaces are spaced apart from each other, and open in respective opposite directions. The base divisional component further includes a cylindrical connecting pipe portion having a connecting passage portion which is a part of the oil passage and which is provided for communication between the first and second passage portions. Also disclosed is a process of forming the resin piping assembly.

This is a Division of U.S. application Ser. No. 16/390,052 filed Apr.22, 2019, which claims the benefit of Japanese Application No.2018-081682 filed Apr. 20, 2018. The disclosures of the priorapplications are hereby incorporated by reference herein in theirentireties.

FIELD OF THE INVENTION

The present invention relates to a resin piping assembly, and a processof forming the resin piping assembly, and more particularly totechniques relating to a resin piping assembly including a plurality ofdivisional components bonded together so as to form an oil passage witha high degree of freedom of design of configuration of the oil passage,while ensuring a high degree of bonding of the divisional components.

BACKGROUND OF THE INVENTION

There is known a resin piping assembly including a plurality ofdivisional components which cooperate to define a circumference of anoil passage along a length of the oil passage and which are bondedtogether with their interfacial surfaces being held in contact with eachother. JP2014-9744A discloses an example of this type of resin pipingassembly, and JP7-80938A discloses a vibration welding process in whichthe plurality of divisional components are pressed for pressing contactof their interfacial surfaces with each other while the divisionalcomponents are vibrated such that their interfacial surfaces are kept inpressing sliding contact with each other, whereby these interfacialsurfaces are welded together due to generated friction heat.

SUMMARY OF THE INVENTION

By the way, where the divisional components are bonded together in thevibration welding process while the divisional components are pressedfor pressing contact of their interfacial surfaces with each other, theinterfacial surfaces are preferably perpendicular to the direction ofpressing of the divisional components against each other. Where the oilpassage of the resin piping assembly is three-dimensional, however, theinterfacial surfaces are accordingly three-dimensional, so that there isa risk of failure to bond together the divisional components with asufficient strength of bonding, due to local areas of the interfacialsurfaces to which a desired pressing force cannot be applied. Namely, adesired pressing force in a direction perpendicular to the interfacialsurfaces can be adequately applied to an entire area of each interfacialsurface, where the divisional components cooperate to define thecircumference of the oil passage in cross section in a plane parallel tothe two-dimensional plane of the two-dimensional oil passage. Where theoil passage is three-dimensional, on the other hand, the interfacialsurfaces have local areas inclined with respect to the two-dimensionalplane perpendicular to the direction of application of the pressingforce. If an angle of inclination of the local areas increases, thepressing force in the direction perpendicular to the inclined localareas is undesirably reduced, so that the permissible three-dimensionalconfiguration of the oil passage is limited due to an upper limit of theangle of inclination permissible to obtain the pressing force requiredto adequately bond together the divisional components. The thus limitedconfiguration of the oil passage will be hereinafter referred to as“limited three-dimensional configuration”.

The present invention was made in view of the background art describedabove. It is therefore an object of the present invention to provide aresin piping assembly including a plurality of divisional componentsbonded together so as to form an oil passage with a high degree offreedom of design of configuration of the oil passage, while ensuring ahigh degree of bonding of the divisional components. Another object ofthe invention is to provide a process of forming such a resin pipingassembly.

The object indicated above is achieved according to the following modesof the present invention:

According to a first mode of the invention, there is provided a resinpiping assembly having an oil passage, comprising: a base divisionalcomponent including a first half component having a first interfacialsurface formed along the oil passage, and a second half component havinga second interfacial surface formed along the oil passage; a firstdivisional component having a third interfacial surface formed along theoil passage, and bonded to the first half component with the first andthird interfacial surfaces being held in contact with each other, so asto form a first passage portion of the oil passage; and a seconddivisional component having a fourth interfacial surface formed alongthe oil passage, and bonded to the second half component with the secondand fourth interfacial surfaces being held in contact with each other,so as to form a second passage portion of the oil passage. Each of thebase divisional component, the first divisional component and the seconddivisional component is formed of a resin material, and the first andsecond interfacial surfaces are spaced apart from each other along alength of the oil passage, and open in respective opposite directions.The base divisional component further includes a cylindrical connectingpipe portion having a connecting passage portion which is a part of theoil passage and which is provided for communication between the firstand second passage portions.

According to a second mode of the invention, the resin piping assemblyaccording to the first mode of the invention is configured such that thefirst interfacial surface of the first half component has a groove atleast partially defining the first passage portion, and the secondinterfacial surface of the second half component has a groove at leastpartially defining the second passage portion. Further, the connectingpipe portion linearly extends along a straight line, and the first andsecond half components are spaced apart from each other in a directionparallel to the straight line. The grooves of the first and secondinterfacial surfaces are open in respective opposite directions parallelto the straight line, and the first and second half components extendfrom the connecting pipe portion in respective opposite directionsperpendicular to the straight line.

According to a third mode of the invention, the resin piping assemblyaccording to the first or second mode of the invention is configuredsuch that at least one of the base divisional component and the firstand second divisional components is provided with a plurality ofintegrally formed hollow nozzle portions each extending in a directionopposite to a direction in which a groove formed in the interfacialsurface of the above-indicated at least one divisional component isopen. Each of the hollow nozzle portions has a delivery nozzle which isopen externally of the hollow nozzle portion.

According to a fourth mode of the invention, the resin piping assemblyaccording to the third mode of the invention is configured such that theconnecting pipe portion linearly extends, and the base divisionalcomponent is provided with the hollow nozzle portions such that thehollow nozzle portions linearly extend parallel to a direction ofextension of the cylindrical connecting pipe portion.

According to a fifth mode of the invention, the resin piping assemblyaccording to any one of the first through fourth modes of the inventionis configured such that the connecting pipe portion linearly extends,and the first half component of the base divisional component isprovided with an integrally formed cylindrical connector port such thatthe connector port linearly extends parallel to a direction of extensionof the connecting pipe portion, in a direction opposite to a directionin which a groove formed in the first interfacial surface is open.

According to a sixth mode of the invention, the resin piping assemblyaccording to any one of the first through fifth modes of the inventiondelivers a lubricant oil to predetermined lubricated portions of a powertransmitting system. The lubricant oil can be used not only to lubricatethose predetermined lubricated portions for preventing or reducingdegrees of their friction and wearing, but also to cool predeterminedheat-generating portions of the power transmitting system. Therefore,the predetermined lubricated portions may be the heat-generatingportions that should be cooled, as well as the portions which aresubjected to friction and should be lubricated.

According to a seventh mode of the invention, there is provided aprocess of forming a resin piping assembly having an oil passage andcomprising: a base divisional component including a first half componenthaving a first interfacial surface formed along the oil passage, and asecond half component having a second interfacial surface formed alongthe oil passage; a first divisional component having a third interfacialsurface formed along the oil passage, and bonded to the first halfcomponent with the first and third interfacial surfaces being held incontact with each other, so as to form a first passage portion of theoil passage; and a second divisional component having a fourthinterfacial surface formed along the oil passage, and bonded to thesecond half component with the second and fourth interfacial surfacesbeing held in contact with each other, so as to form a second passageportion of the oil passage, wherein each of the base divisionalcomponent, the first divisional component and the second divisionalcomponent is formed of a resin material, and the first and secondinterfacial surfaces are spaced apart from each other along a length ofthe oil passage, and open in respective opposite directions, the basedivisional component further including a cylindrical connecting pipeportion having a connecting passage portion which is a part of the oilpassage and which is provided for communication between the first andsecond passage portions, the process comprising: a forming step to formthe base divisional component, the first divisional component and thesecond divisional component by an injection molding process,respectively; a first bonding step to bond the first divisionalcomponent to the first half component of the base divisional component,by pressing contact of the first interfacial surface of the first halfcomponent with the third interfacial surface of the first divisionalcomponent; and a second bonding step to bond the second divisionalcomponent to the second half component of the base divisional component,by pressing contact of the second interfacial surface of the second halfcomponent with the fourth interfacial surface of the second divisionalcomponent.

According to an eighth mode of the invention, the process according tothe seventh mode of the invention is arranged such that the firstbonding step includes a vibration welding step in which the firstinterfacial surface of the first half component and the thirdinterfacial surface of the first divisional component are held inpressing sliding contact with each other, while the second bonding stepincludes a vibration welding step in which the second interfacialsurface of the second half component and the fourth interfacial surfaceof the second divisional component are held in pressing sliding contactwith each other. The divisional components are bonded together in avibration welding operation in which the divisional components aresubjected to vibration and welding due to friction heat generated by thevibration, while the divisional components are pressed against eachother. However, the divisional components may be bonded together whilethey are pressed against each other during their vibration after theirinterfacial surfaces are heated by exposure to infrared rays.

According to a ninth mode of the invention, the process according to theseventh or eighth mode of the invention is adapted to the resin pipingassembly wherein the first interfacial surface of the first halfcomponent has a groove partially defining the first passage portion,while the second interfacial surface of the second half component has agroove partially defining the second passage portion, and the connectingpipe portion linearly extends along a straight line, and the first andsecond half components are spaced apart from each other in a directionparallel to the straight line, the grooves of the first and secondinterfacial surfaces being open in respective opposite directionsparallel to the straight line, and the first and second half componentsextending from the connecting pipe portion in respective oppositedirections perpendicular to the straight line. The process of formingthe resin piping assembly according to the ninth mode of the inventionis arranged such that the forming step is implemented to form the basedivisional component integrally with the first and second halfcomponents having the respective grooves, and the connecting pipeportion, by the injection molding process, by using a molding devicehaving a pair of forming molds which are movable toward and away fromeach other in the direction parallel to the straight line.

According to a tenth mode of the invention, the process according to theninth mode of the invention is adapted to the resin piping assemblywherein the second half component of the base divisional component isprovided with a plurality of hollow nozzle portions each linearlyextending in a direction of the straight line and a direction oppositeto a direction in which the groove formed in the second interfacialsurface is open, each of the hollow nozzle portions having a deliverynozzle which is open externally of the hollow nozzle portion. Theprocess of forming the resin piping assembly according to the tenth modeof the invention is arranged such that the forming step is implementedto form the base divisional component integrally with the hollow nozzleportions, by the injection molding process with the molding device.

According to an eleventh mode of the invention, the process according tothe ninth or tenth mode of the invention is adapted to the resin pipingassembly wherein the first half component of the base divisionalcomponent is provided with a cylindrical connector port linearlyextending in a direction of the straight line and a direction oppositeto a direction in which the groove formed in the first interfacialsurface is open. The process of forming the resin piping assemblyaccording to the eleventh mode of the invention is arranged such thatthe forming step is implemented to form the base divisional componentintegrally with the cylindrical connector port, by the injection moldingprocess with the molding device.

In the resin piping assembly according to the first mode of theinvention, the resin piping assembly comprises the base divisionalcomponent including the first and second half components connected toeach other through the connecting pipe portion, and the first and seconddivisional components cooperating with the respective first and secondhalf components to form the respective first and second passage portionsof the oil passage. For bonding the first and second divisionalcomponents to the respective first and second half components bypressing contact of the first and third interfacial surfaces with eachother, and by pressing contact of the second and fourth interfacialsurfaces with each other, each of those first through fourth interfacialsurfaces is required to have a two-dimensional configuration or alimited three-dimensional configuration, so that a desired pressingforce can be applied to an entire area of each of the interfacialsurfaces. Accordingly, each of the first and second passage portions isalso required to have a two-dimensional configuration or a limitedthree-dimensional configuration. In the resin piping assembly accordingto the present first mode of the invention, however, the configurationsof the first and second passage portions can be designed independentlyof each other, so as to permit application of the desired pressing forceto the entire area of each interfacial surface. Further, the first andsecond passage portions are spaced apart from each other and are held incommunication with each other through the connecting pipe portion, sothat the resin piping assembly has a high degree of freedom of design ofconfiguration of the oil passage including the connecting passageportion. Accordingly, the present resin piping assembly can be formed tohave a comparatively complicated three-dimensional configuration whileensuring a high degree of bonding of the first and second divisionalcomponents to the first and second half components of the basedivisional component.

Where the first and second divisional components are bonded to therespective first and second half components with an adhesive agent beingapplied to their interfacial surfaces, for instance, it is not requiredto apply a large pressing force to the interfacial surfaces. In thiscase, the configurations of the interfacial surfaces have a high degreeof freedom of design, so that there is a reduced limitation regardingthe configurations of the first and second passage portions, whereby theresin piping assembly has a high degree of freedom of design ofconfiguration of the oil passage as a whole, as well as a desiredstrength of bonding of the first and second divisional components to therespective first and second half components. Thus, the resin pipingassembly according to the first mode of the invention does notnecessarily require application of a large pressing force to theinterfacial surfaces for their mutual bonding.

In the resin piping assembly according to the second mode of theinvention, the first and second interfacial surfaces of the first andsecond half components have the respective grooves, and the connectingpipe portion linearly extends along the straight line. Further, thefirst and second half components are spaced apart from each other in thedirection parallel to the straight line, and the grooves of the firstand second interfacial surfaces are open in the respective oppositedirections parallel to the straight line. The first and second halfcomponents extend from the connecting pipe portion in the respectiveopposite directions perpendicular to the straight line. Accordingly, thebase divisional component including the first and second half componentsand the connecting pipe portion can be formed as a one-piece body withthe first and second interfacial surfaces having the respective grooves,by an injection molding process or a press-forming process, for example,by using a molding device provided with a pair of forming molds whichare movable toward and away from each other in the direction parallel tothe above-indicated straight line. Thus, the base divisional componentcan be easily and economically formed.

In the resin piping assembly according to the third mode of theinvention, at least one of the base divisional component and the firstand second divisional components is provided with the plurality ofintegrally formed hollow nozzle portions each extending in the directionopposite to the direction in which the groove formed in the interfacialsurface of the above-indicated at least one divisional component isopen. The hollow nozzle portions permit extension of the oil passage,without reducing the strength of bonding of the first and seconddivisional components to the base divisional component. Further, thehollow nozzle portions formed integrally with the above-indicated atleast one divisional component permit economical manufacture of theresin piping assembly with a reduced number of parts, than whereseparately formed nozzles are fixed to a resin piping assembly withscrews or any other fastening members.

In the resin piping assembly according to the fourth mode of theinvention, the connecting pipe portion linearly extends, and the basedivisional component is provided with the hollow nozzle portions suchthat the hollow nozzle portions linearly extend parallel to thedirection of extension of the cylindrical connecting pipe portion.Accordingly, the base divisional component including the connecting pipeportion and the hollow nozzle portions can be formed as a one-piecebody, by an injection molding process or a press-forming process, forexample, by using a molding device provided with a pair of forming moldswhich are movable toward and away from each other in the directionparallel to the above-indicated straight line. Thus, the base divisionalcomponent can be easily and economically formed.

In the resin piping assembly according to the fifth mode of theinvention, the connecting pipe portion linearly extends, and the firsthalf component of the base divisional component is provided with theintegrally formed cylindrical connector port such that the connectorport linearly extends parallel to the direction of extension of theconnecting pipe portion, in the direction opposite to the direction inwhich the groove formed in the first interfacial surface is open.Accordingly, the cylindrical connector port can be formed, withoutreducing the strength of bonding of the first divisional component tothe first half component of the base divisional component. Further, thecylindrical connector port formed integrally with the base divisionalcomponent permits economical manufacture of the resin piping assemblywith a reduced number of parts, than where a separately formed connectorport is fixed to a resin piping assembly with screws or any otherfastening members. In addition, since the connector port is formed so asto extend along the straight line parallel to the direction of extensionof the connecting pipe portion, the base divisional component includingthe connecting pipe portion and the connector port can be formed as aone-piece body, by an injection molding process or a press-formingprocess, for example, by using a molding device provided with a pair offorming molds which are movable toward and away from each other in thedirection parallel to the above-indicated straight line. Thus, the basedivisional component can be easily and economically formed.

The resin piping assembly according to the sixth mode of the inventiondelivers the lubricant oil to the predetermined lubricated portions ofthe power transmitting system. Since the resin piping assembly has ahigh degree of freedom of design of configuration of the oil passage,the resin piping assembly can be compactly disposed in a complicatednarrow space within a casing of the power transmitting system, and candeliver the lubricant oil exactly to the predetermined lubricatedportions of the power transmitting system, in a pin-pointing manner.

In the process according to the seventh mode of the invention, the basedivisional component, the first divisional component and the seconddivisional component are formed by the injection molding process,respectively, and the first and second divisional components are bondedto the respective first and second half components of the basedivisional component, by pressing the first and second divisionalcomponents against the respective first and second half components.Accordingly, the present process has substantially the same advantagesas the resin piping assembly according to the first mode of theinvention.

In the process according to the eighth mode of the invention, each ofthe first bonding step to bond the first divisional component to thefirst half component of the base divisional component, and the secondbonding step to bond the second divisional component to the second halfcomponent of the base divisional component is implemented by a vibrationwelding step wherein a desired pressing force should be applied to anentire area of each of the first through fourth interfacial surfaces,for ensuring a required strength of bonding of the first and seconddivisional components to the respective first and second halfcomponents. Since all of the interfacial surfaces have two-dimensionalor limited three-dimensional configurations, the desired pressing forcecan be applied to the entire area of each interfacial surface in thevibration welding process, whereby the first and second divisionalcomponents can be adequately bonded to the respective first and secondhalf components of the base divisional component.

The process according to the ninth mode of the invention is adapted tothe resin piping assembly wherein the first and second interfacialsurfaces of the first and second half components have the respectivegrooves partially defining the respective first and second passageportions, and the first and second half components are spaced apart fromeach other in the direction parallel to the direction of extension ofthe connecting pipe portion. The grooves are open in the respectiveopposite directions parallel to the direction of extension of theconnecting pipe portion, and the first and second half components extendfrom the connecting pipe portion in the respective opposite directionsperpendicular to the direction of extension of the connecting pipeportion. According to this ninth mode of the invention, the process offorming the resin piping assembly is arranged such that the forming stepis implemented to form the base divisional component integrally with thefirst and second half components having the respective grooves, and theconnecting pipe portion, by the injection molding process, by using themolding device having the pair of forming molds which are movable towardand away from each other in the direction parallel to the direction ofextension of the connecting pipe portion. Accordingly, the basedivisional component having the hollow nozzle portions can be easily andeconomically formed. The molding device need not be provided with asliding mold movable in the direction perpendicular to the direction ofextension of the connecting pipe portion, so that the molding device canbe economically manufactured with a comparatively simple structure.

The process according to the tenth mode of the invention is adapted tothe resin piping assembly wherein the second half component of the basedivisional component is provided with the plurality of hollow nozzleportions each linearly extending in the direction of the straight lineand the direction opposite to the direction in which the groove formedin the second interfacial surface is open, and each of the hollow nozzleportions has the delivery nozzle which is open externally of the hollownozzle portion. The process of forming the resin piping assemblyaccording to the tenth mode of the invention is arranged such that theforming step is implemented to form the base divisional componentintegrally with the hollow nozzle portions, by the injection moldingprocess with the molding device. Accordingly, the base divisionalcomponent with the hollow nozzle portions can be easily and economicallyformed. The process according to the eleventh mode of the invention isadapted to the resin piping assembly wherein the first half component ofthe base divisional component is provided with the cylindrical connectorport linearly extending in the direction of the straight line and thedirection opposite to the direction in which the groove formed in thefirst interfacial surface is open. The process of forming the resinpiping assembly according to the eleventh mode of the invention isarranged such that the forming step is implemented to form the basedivisional component integrally with the connector port, by theinjection molding process with the molding device. Accordingly, the basedivisional component with the connector port can be easily andeconomically formed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing an arrangement of a powertransmitting system of a hybrid vehicle, which is provided with alubricating device including an oil piping assembly (resin pipingassembly) according to one embodiment of the invention;

FIG. 2 is a hydraulic circuit diagram illustrating the lubricatingdevice of the power transmitting system shown in FIG. 1;

FIG. 3 is a schematic perspective view showing an oil piping assemblywhich provides a first oil supply passage of the lubricating deviceshown in FIG. 2;

FIG. 4 is a front elevational view of the oil piping assembly of FIG. 3as seen in a width or transverse direction of the hybrid vehicle;

FIG. 5 is a side elevational view of the oil piping assembly as seen inthe leftward direction of FIG. 4;

FIG. 6 is a perspective view of three divisional components of the oilpiping assembly before the divisional components are bonded together toform the oil piping assembly;

FIG. 7 is a cross sectional view of the oil piping assembly taken in adirection indicated by lines VII-VII in FIG. 4;

FIG. 8 is a cross sectional view of a molding device for forming thebase divisional component shown in FIG. 6;

FIG. 9 is a cross sectional view of a molding device for forming thefirst divisional component shown in FIG. 6;

FIG. 10 is a cross sectional view of a molding device for forming thesecond divisional component shown in FIG. 6;

FIG. 11 is a side elevational view corresponding to that of FIG. 5,showing an oil piping assembly according to another embodiment of thisinvention;

FIG. 12 is a side elevational view corresponding to that of FIG. 5,showing an oil piping assembly according to a further embodiment of theinvention; and

FIG. 13 is a cross sectional view of a molding device for forming a basedivisional component shown in FIG. 12.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The resin piping assembly according to the present invention is suitablyapplicable to a lubricating device of a power transmitting system of avehicle, for delivering the lubricant oil to predetermined lubricatedportions of the power transmitting system. However, the present resinpiping assembly is equally applicable to a lubricating device of a powertransmitting system other than the vehicular power transmitting system.Further, the present resin piping assembly may be used for various otherpurposes, for example, for delivering a fluid such as water other thanthe lubricant oil. Examples of the lubricated portions of the powertransmitting system include: power transmitting gears meshing with eachother; a transmission belt; bearings rotatably supporting rotary shaftsof the power transmitting system; and mutually frictionally contactingportions and heat generating portions of electric motors and generatorsof hybrid or electric vehicles, which are required to be lubricated orcooled during power transmission. The resin piping assembly according tothe present invention may be used to deliver the lubricant oil from theoil pump directly to the predetermined lubricated portions, but may beused to deliver the lubricant oil to any other portions or for any otherpurposes, for instance, to deliver the lubricant oil to an oil cooler orany other heat exchanging device, or to hydraulic switching valves andhydraulic pressure control valves, or to deliver the lubricant oil fromthe oil cooler or any other heat exchanging device, or from thehydraulic switching valves or hydraulic pressure control valves, to thelubricated portions.

While the resin piping assembly is basically formed of a synthetic resinmaterial, reinforcing metallic members may be embedded in the resinpiping assembly, by an insert-forming process. Further, the resin pipingassembly including at least three divisional components consisting ofthe base divisional component and the first and second divisionalcomponents may consist of four or more divisional components formedintegrally with each other. For instance, the second divisionalcomponent may consist of two half components, like the base divisionalcomponent. In this case, the resin piping assembly includes fourdivisional components consisting of the base divisional component, thefirst divisional component, and the two half components of the seconddivisional component. Alternatively, the base divisional component mayinclude three half components consisting of the above-indicated firstand second half components, and a third half component connected to thesecond half component through another connecting pipe portion. In thiscase, a third divisional component is bonded to the third half componentof the base divisional component. The oil passage formed through theresin piping assembly may have a comparatively simple two-dimensionalcrank configuration consisting of the first passage portion, the secondpassage portion each extending linearly, and the connecting passageportion connected at its opposite ends to the first and second passageportions such that the connecting passage portion is perpendicular tothe first and second passage portions. Alternatively, the oil passageincluding the first and second passage portions may have a limitedthree-dimensional configuration which permits the divisional componentsof the resin piping assembly to be adequately bonded together with arequired pressing force. The limited three-dimensional configuration ispreferably designed such that a permissible upper limit of an angle ofinclination of the first and second passage portions with respect to aplane perpendicular to the direction of application of the pressingforce is 60°, desirably 45°, where the first and second divisionalcomponents are bonded to the base divisional component by a weldingprocess. The permissible upper limit of the angle of inclination may besuitably determined depending upon the specific process or manner ofbonding of the plurality of divisional components. Although thedivisional components are preferably bonded together by the weldingprocess in which synthetic resin materials of the divisional componentsare pressed and melted due to friction or heat, the divisionalcomponents may be bonded together with an adhesive agent while apressing force is applied to the divisional components. While theprinciple of the process of forming the resin piping assembly accordingto the present invention requires the first and second divisionalcomponents to be bonded to the base divisional component with pressingcontact of their interfacial surfaces with each other, the resin pipingassembly per se according to the present invention does not requireapplication of a pressing force to the interfacial surfaces of thedivisional components during their mutual bonding.

The first and second half components of the base divisional componentmay be formed so as to suitably determine two directions in which therespective third and fourth interfacial surfaces of the first and seconddivisional components are pressed against the respective first andsecond interfacial surfaces of the first and second divisionalcomponents along a straight line. For instance, the above-indicated twodirections are opposite to each other, or perpendicular to each other.Irrespective of these two directions with respect to each other, thebase divisional component can be formed as a one-piece body by injectionmolding, by using a molding device provided with three or more moldswhich are movable in two or more directions (along two or more axes).Where the two directions are opposite to each other, while theconnecting pipe portion linearly extends along a straight line, theconnecting pipe portion can be formed during an injection moldingprocess to form the base divisional component. However, the connectingpipe portion, and the connecting passage portion formed through theconnecting pipe portion may be formed by machining operations, forinstance, after the injection molding process. Further, the connectingpipe portion need not be formed so as to linear extend along a straightline.

At least one of the first interfacial surface of the first halfcomponent of the base divisional component and the third interfacialsurface of the first divisional component has a groove (elongate recess)at least partially defining the first passage portion, and at least oneof the second interfacial surface of the second half component of thebase divisional component and the fourth interfacial surface of thesecond divisional component has a groove (elongate recess) at leastpartially defining the second passage portion. Namely, the first andthird interfacial surfaces, and/or the second and fourth interfacialsurfaces need not have two symmetrical semi-circular shapes in crosssection in a plane perpendicular to a direction of extension of the oilpassage (first or second passage portion), but may have respectivedifferent arcuate dimensions in the above-indicated cross section. Forinstance, the arcuate dimensions of the two interfacial surfaces to bebonded together may have a ratio of 1:2 or 1:3. Further, one of theabove-indicated two interfacial surfaces may have no groove, while onlythe other interfacial surface has a semi-circular, U-shaped or V-shapedgroove, for example. The oil passage may have a circular, elliptical,triangular, quadrangular or any other polygonal, or any other crosssectional shape. The grooves are desirably formed in the interfacialsurfaces during formation of the divisional components by injectionmolding, for instance, but may be formed by machining operations afterthe formation of the divisional components. The interfacial surfacehaving the groove is considered to be defined by the periphery of anopening of the groove.

Each of the first and second passage portions of the oil passage isconnected at its one end to the connecting pipe portion, for example, sothat the first and second passage portions are connected to each otherthrough the connecting pipe portion, such that the two passage portionsextend from the connecting pipe portion in respective oppositedirections. However, the connecting pipe portion may be connected to alongitudinally intermediate part of at least one of the first and secondpassage portions, so that the oil passage has a plurality of branchpassage sections. The base divisional component and the first and seconddivisional components are provided with a plurality of integrally formedand outwardly extending hollow nozzle portions, and an integrally formedand cylindrical connector port, as needed, such that the hollow nozzleportions and connector port linear extend along straight lines parallelto the connecting pipe portion, in the direction opposite to thedirection in which the grooves formed in the interfacial surfaces areopen. However, the hollow nozzle portions and the connector port may bereplaced by delivery nozzles and a connector fitting directlycommunicating with the first or second passage portion. The connectorport may be provided to introduce a fluid into the resin pipingassembly, or to deliver the fluid from the resin piping assembly. Thedelivery nozzles and the connector fitting may be formed duringformation of the divisional components, by using a molding deviceincluding a sliding mold which is mechanically moved by a cam, insynchronization with a movement of a movable mold, for example. However,the delivery nozzles and the connector fitting may be formed bymachining operations after the divisional components are formed.Passages formed through the hollow nozzle portions and a through-hole ofthe connector port may also be formed during formation of the divisionalcomponents by an injection molding process, for example. However, thepassages and through-hole may be formed by machining operations afterformation of the divisional components, and need not be formed so as toextend in the direction parallel to the direction of extension of theconnecting pipe portion.

While the base divisional component and the first and second divisionalcomponents are preferably formed as a one-piece body by an injectionmolding process, these divisional components may be formed by a pressforming process. Further, those divisional components may be subjectedto machining or other operations after formation of the components. Thefirst bonding step to bond the first divisional component to the firsthalf component of the base divisional component, and the second bondingstep to bond the second divisional component to the second halfcomponent of the base divisional component may be implemented in thisorder of description, or vice versa, or at the same time, if possible.

Preferred embodiments of the present invention will be described indetail by reference to the drawings. It is to be understood that thedrawings are simplified and transformed as needed, and do notnecessarily accurately represent dimensions and shapes of variouselements of the embodiment.

Reference is first made to FIG. 1, which is the schematic view showingan arrangement of a hybrid vehicle 10 including a transaxle 12 providedwith a lubricating device 40 (described below by reference to FIG. 2)according to a first embodiment of this invention. The transaxle 12includes a power transmitting mechanism 16 having a plurality of axeswhich are shown in a common plane of the view of FIG. 1. The transaxle12 is configured to transmit an output of a drive power source in theform of an engine 20 to left and right drive wheels 38, and is of atransversely mounted type installed on the hybrid vehicle 10 of an FFtype, for example, such that the plurality of axes of the powertransmitting mechanism 16 of a gear type are parallel to a width ortransverse direction of the hybrid vehicle 10. The power transmittingmechanism 16 is accommodated within a casing 14. The engine 20 is aninternal combustion engine such as a gasoline or diesel engine, whichgenerates a vehicle drive force by combustion of a fuel. The transaxle12 is a power transmitting system, and the casing 14 consists of aplurality of members as needed.

The power transmitting mechanism 16 has first through fourth axes S1-S4substantially parallel to the width direction of the hybrid vehicle 10.On the first axis S1, there are disposed: an input shaft 22 connected tothe engine 20 functioning as the drive power source; a planetary gearset 24 of a single-pinion type; and a first motor/generator MG1. Theplanetary gear set 24 and the first motor/generator MG1 function as anelectrically controlled differential portion 26. The planetary gear set24 functions as a differential mechanism, and includes a carrier 24 cconnected to the input shaft 22, a sun gear 24 s connected to the firstmotor/generator MG1, and a ring gear 24 r provided with an engine outputgear Ge. The carrier 24 c, sun gear 24 s and ring gear 24 r respectivelycorrespond to first, second and third rotary elements, while the firstmotor/generator MG1 corresponds to a differential control motor. Thefirst motor/generator MG1 is operated selectively as an electric motoror an electric generator. When the first motor/generator MG1 is operatedas the electric generator, a rotating speed of the sun gear 24 s iscontinuously controlled by a regenerative control of the firstmotor/generator MG1, so that an operating speed of the engine 20 iscontinuously varied, and a rotary motion of the engine 20 is output fromthe engine output gear Ge. When the sun gear 24 s is placed in a freelyrotatable state with torque of the first motor/generator MG1 beingzeroed, the engine 20 and the power transmitting mechanism 16 aredisconnected from each other, so that dragging of the engine 20 by thepower transmitting mechanism 16 is prevented.

On the second axis S2, there is disposed a speed reducing gear device 30including a shaft 28 provided at opposite axial ends of the shaft 28with a large-diameter speed reducing gear Gr1 and a small-diameter speedreducing gear Gr2. The large-diameter speed reducing gear Gr1 is held inmeshing engagement with the engine output gear Ge, and a motor outputgear Gm of a second motor/generator MG2 disposed on the third axis S3.The second motor/generator MG2 is operated selectively as an electricmotor or an electric generator. The second motor/generator MG2 serves asa drive power source for driving the hybrid vehicle 10 when the secondmotor/generator MG2 is operated as the electric motor. Thus, the secondmotor/generator MG2 is operable as a vehicle driving electric motor.

The small-diameter speed reducing gear Gr2 is held in meshing engagementwith a differential ring gear Gd of a differential gear device 32disposed on the fourth axis S4, so that drive forces of the engine 20and the second motor/generator MG2 are distributed to left and rightdrive shafts 36 through the differential gear device 32, and transmittedto the left and right drive wheels 38. The engine output gear Ge, thelarge-diameter speed reducing gear Gr1, the small-diameter speedreducing gear Gr2 and the differential ring gear Gd primarily constitutea gear mechanism. The fourth axis S4 of the first through fourth axesS1-S4 is the axis located at the lowest position in the hybrid vehicle10, and a bottom portion of the casing 14 serves as an oil reservoir 46storing an oil (lubricant oil) 48, as shown in FIG. 2, so that a lowerportion of the differential gear device 32 is immersed in a bath of theoil 48.

The hybrid vehicle 10 constructed as described above is placed in aselected one of an EV (electric vehicle) drive mode and an HV (hybridvehicle) drive mode, according to a drive mode switching map and on thebasis of a required vehicle drive force (as represented by an operationamount of an accelerator pedal) and a running speed V of the hybridvehicle 10, for example. In the EV drive mode, the hybrid vehicle 10 isdriven with the second motor/generator MG2 operated as the drive powersource, while the engine 20 is held at rest. This EV drive mode isselected when the required vehicle drive force is comparatively small,namely, the hybrid vehicle 10 is in a low-load running state. In the EVdrive mode, a fuel supply to the engine 20 is stopped, and the torque ofthe first motor/generator MG1 is zeroed, so that the sun gear 24 s ofthe planetary gear set 24 is freely rotatable, and the firstmotor/generator MG1 is held substantially at rest, even in a runningstate of the hybrid vehicle 10. In the HV drive mode, the hybrid vehicle10 is driven with the engine 20 operated as the drive power source,while a regenerative operation of the first motor/generator MG1 iscontrolled. The HV drive mode is selected when the required vehicledrive force is comparatively large, namely, the hybrid vehicle 10 is ina high-load running state. In this HV drive mode, the secondmotor/generator MG2 is operated as the drive power source whengeneration of an assisting torque is required to accelerate the hybridvehicle 10, for example, or is kept operated as the drive power source.

The hybrid vehicle 10 may be placed in an engine drive mode in place ofthe above-described HV drive mode, or as well as in the HV drive mode.In the engine drive mode, only the engine 20 is operated as the drivepower source. Although the arrangement of the transaxle 12 of the hybridvehicle 10 has been described for illustrative purpose only, thetransaxle 12 may be constructed with various changes or modifications.For example, the planetary gear set 24 of the single-pinion type may bereplaced by a planetary gear set of a double-pinion type, or a pluralityof planetary gear sets. Further, the second motor/generator MG2 may bedisposed on the first axis S1, and the electrically controlleddifferential portion 26 may be replaced by a mechanically operatedtransmission.

In the present embodiment of the invention, the transaxle 12 of thehybrid vehicle 10 is provided with the above-indicated lubricatingdevice 40 shown in FIG. 2. The lubricating device 40 includes a firstoil pump P1 and a second oil pump P2 as an oil pumping device. The firstand second oil pumps P1 and P2 are connected to respective first andsecond oil supply passages 42 and 44 which are independent of eachother, and which are assigned to respective groups of predeterminedlubricated portions of the power transmitting mechanism 16. As shown inFIG. 1, the first oil pump P1 is a mechanical pump mechanically operatedby a pump driving gear Gp held in meshing engagement with thedifferential ring gear Gd, while the second oil pump P2 is a mechanicalpump mechanically operated by the engine 20 through the input shaft 22.The first oil pump P1 may be modified such that the pump driving gear Gpis held in meshing engagement with the large-diameter speed reducinggear Gr1 or the small-diameter speed reducing gear Gr2, which is rotatedin synchronization with the differential ring gear Gd. The second oilpump P2 is an oil pump operated by a drive power source different from avehicle drive force output portion in the form of the differential geardevice 32, that is, an oil pump operated by the engine 20. However, thesecond oil pump P2 may be replaced by an electrically operated oil pumpoperated by an exclusive pump driving electric motor.

The first and second oil pumps P1 and P2 described above are configuredto suck the oil 48 from the oil reservoir 46 located in the bottomportion of the casing 14, and to deliver the oil 48 through the firstand second oil supply passages 42 and 44. A space formed within the oilreservoir 46, which is constituted by the bottom portion of the casing14, is divided by a first partition wall 50 into a rear portion as seenin a longitudinal direction of the hybrid vehicle 10, and the otherportion. This rear portion of the space serves as a first oil reservoirportion 52 located below the differential gear device 32. Theabove-indicated other portion of the space is divided by a secondpartition wall 53 into two parts located adjacent to each other in thelongitudinal direction of the hybrid vehicle 10, namely, a second oilreservoir portion 54 located adjacent to the first oil reservoir portion52, and a third oil reservoir portion 56 located adjacent to the secondoil reservoir portion 54. A suction port 58 of the first oil pump P1 isdisposed within the second oil reservoir portion 54, while a suctionport 60 of the second oil pump P2 is disposed within the third oilreservoir portion 56. These two suction ports 58 and 60 are connected tothe respective first and second oil pumps P1 and P2 through respectivesuction passages.

The first and second partition walls 50 and 53 function as an oil-flowrestricting portion which allows but restricts flows of the oil 48between the first and second oil reservoir portions 52 and 54, andbetween the second and third oil reservoir portions 54 and 56, such thatbaths of the oil 48 in the first, second and third oil reservoirportions 52, 54 and 56 have different levels, when the first and secondoil pumps P1 and P2 are operated. Namely, when the first and second oilpumps P1 and P2 are both held at rest while the hybrid vehicle 10 isstationary, the baths of the oil 48 in all of the three oil reservoirportions 52, 54 and 56 have the same level, that is, a static level Lstindicated by a one-dot chain line in FIG. 2, which level Lst is higherthan upper ends of the first and second partition walls 50 and 53, sincethe oil 48 delivered to the various lubricated portions of the transaxle12 drops down into the oil reservoir 46 while the oil pumps P1 and P2are held at rest. When the oil pumps P1 and P2 are operated duringrunning of the hybrid vehicle 10, however, the oil 48 is delivered fromthe oil pumps P1 and P2 to the various lubricated portions of thetransaxle 12, so that a volume of the oil 48 staying in the oilreservoir 46 is reduced, whereby the levels of the baths of the oil 48in the oil reservoir portions 52, 54 and 56 are lowered below the upperends of the partition walls 50 and 53, and to respective differentheights indicated by solid lines in FIG. 2, due to the flow restrictingfunction of the partition walls 50 and 53.

The upper ends of the first and second partition walls 50 and 53 arehigher than the lower end of the differential gear device 32, so that alower portion of the differential gear device 32 is immersed in the bathof the oil 48 in the first oil reservoir portion 52 while the level ofthe oil 48 in the oil reservoir 46 is higher than the upper ends of thepartition walls 50 and 53 in the stationary state of the hybrid vehicle10. When the hybrid vehicle 10 is started in this stationary state inwhich the differential gear device 32 is partially immersed in the bathof the oil 48 in the first oil reservoir portion 52, the oil 48 issplashed up by the differential ring gear Gd, and is scattered over thelubricated portions of the transaxle 12, so that these lubricatedportions can be sufficiently lubricated during starting of the hybridvehicle 10 wherein the first oil pump P1 has difficulty to deliver asufficient amount of the oil 48.

While the oil pumps P1 and P2 are operated during running of the hybridvehicle 10, on the other hand, the level of the oil 48 is lowered belowthe upper ends of the partition walls 50 and 53 as a result of splashingof the oil 48 by the differential ring gear Gd rotated according to therunning speed V of the hybrid vehicle 10, and suction of the oil 48 bythe oil pumps P1 and P2. The level of the bath of the oil 48 in thefirst oil reservoir portion 52 is determined by a difference between theamount of the oil 48 splashed up by the differential ring gear Gd andthe amount of the oil 48 returned back into the first oil reservoirportion 52, and the level of the bath of the oil 48 in the second oilreservoir portion 54 is determined by a difference between the amount ofthe oil 48 sucked by the first oil pump P1 and the amount of the oil 48returned back into the second oil reservoir portion 54, while the levelof the bath of the oil 48 in the third oil reservoir portion 56 isdetermined by a difference between the amount of the oil 48 sucked bythe second oil pump P2 and the amount of the oil 48 returned back intothe third oil reservoir portion 56. In the present embodiment, thevolume of the first oil reservoir portion 52 is determined, namely, theposition and shape of the first partition wall 50 are determined suchthat the level of the bath of the oil 48 in the first oil reservoirportion 52 can be lowered to a lowest position, so that agitation of theoil 48 by the rotary motion of the differential gear device 32 isrestricted to reduce a power loss due to the agitation. Further, thelevels of the baths of the oil 48 in the second and third oil reservoirportions 54 and 56 in which the suction ports 58 and 60 are disposed aremade higher than the level in the first oil reservoir portion 52, sothat it is possible to reduce a risk of air suction by the oil pumps P1and P2 due to exposure of the suction ports 58 and 60 above the levelsof the baths of the oil 48 in the second and third oil reservoirportions 54 and 56, whereby the oil 48 can be adequately sucked by theoil pumps P1 and P2, and stably delivered to the predeterminedlubricated portions of the transaxle 12.

In addition, the second and third oil reservoir portions 54 and 56 whichare separated from each other by the second partition wall 53 in thelongitudinal direction of the hybrid vehicle 10 have comparatively smalldimensions in the longitudinal direction, making it possible to reducean amount of variation, in the longitudinal direction, of a distancefrom the bottoms of the oil reservoir portions 54 and 56 to the oillevels of the baths of the oil 48 therein, which variation takes placedue to a change of attitude of the hybrid vehicle 10 according to agradient of the roadway surface, or acceleration or deceleration of thehybrid vehicle 10, whereby it is possible to more effectively reduce therisk of air suction by the oil pumps P1 and P2 the suction ports 58 and60 of which are disposed in the oil reservoir portions 54 and 56. Inthis respect, it is noted that the first and second partition walls 50and 53 may have the same height dimension, and that the first and secondpartition walls 50 and 53 need not be provided.

The first oil pump P1 is operatively connected to and operated by thevehicle drive force output portion in the form of the differential geardevice 32, and the first oil supply passage 42 connected to a deliveryport of the first oil pump P1 is provided to deliver the oil 48 to thelubricated portions of the power transmitting mechanism 16. Thelubricated portions include bearings 62 and gears 64 (Ge, Gr1, Gr2, Gd,Gm, Gp) incorporated in the power transmitting mechanism 16. The firstoil pump P1 is operatively connected to and operated by the differentialgear device 32, and is therefore operated even in the EV drive mode inwhich the engine 20 is held at rest, so that the first oil pump P1 isable to suck the oil 48 by an amount according to the vehicle runningspeed V, and to deliver the oil 48 to the lubricated portions. That is,the vehicle running speed V corresponds to an operating speed of thefirst oil pump P1, and to a volume of the oil 48 delivered from thefirst oil pump P1. Although the differential gear device 32 islubricated with the oil 48 splashed up by the differential ring gear Gd,the differential gear device 32 may be lubricated with the oil 48delivered through the first oil supply passage 42. Further, an oilstorage may be provided as needed to ensure a stable supply of the oil48 to the first oil pump P1, for preventing a risk of air suction by thefirst oil pump P1.

The second oil supply passage 44 is connected to a delivery port of thesecond oil pump P2, to deliver the oil 48 to the predeterminedlubricated portions located upwardly of the second and third oilreservoir portions 54 and 56. These lubricated portions include: theinput shaft 22; the planetary gear set 24; and the first motor/generatorMG1. The second oil supply passage 42 is provided with a heat exchanger66 to cool the oil 48, so that the cooled oil 48 is delivered to thefirst motor/generator MG1 and the second motor/generator MG2, forcooling and preventing overheating of the motor/generator MG1 and themotor/generator MG2. For example, the heat exchanger 66 is an oil coolerof an air cooling or water cooling type for cooling the oil 48. Sincethe engine 20 used to operate the second oil pump P2 can be operatedeven while the hybrid vehicle 10 is stationary, an adequate amount ofthe oil 48 can be sucked by and delivered to the lubricated portionsfrom the second oil pump P2, irrespective of a variation of the vehiclerunning speed V, even while the hybrid vehicle 10 is stationary. It isnoted that the second oil pump P2 may be dispensed with, provided thefirst oil pump P1 is adapted to deliver the oil 48 also to themotor/generator MG1 and motor/generator MG2, and the planetary gear set24.

FIG. 3 is the schematic perspective view showing an oil piping assembly70 according to a first embodiment of this invention, which has thefirst oil supply passage 42. The oil piping assembly 70 is formedseparately from the casing 14, and is provided with a plurality offixing portions 72 which are to be fixed to an inner wall surface of thecasing 14 or to an outer surface of a housing of the first oil pump P1with fastening bolts 74, such that the oil piping assembly 70 is locatedat a predetermined position within the casing 14. The oil pipingassembly 70 has a plurality of hollow nozzle portions 76 from which theoil 48 is ejected to the bearings 62 and the gears 64. The oil pipingassembly 70 has a three-dimensionally bent generally hollow structure.The oil piping assembly 70 is a resin piping assembly formed of asynthetic resin material so as to define an oil passage in the form ofthe first oil supply passage 42 through which the oil 48 flows. The oil48 is a lubricant oil for lubricating the lubricated portions in theform of the bearings 62 and gears 64.

FIG. 4 is the front elevational view of the oil piping assembly 70 asseen in the width or transverse direction of the hybrid vehicle 10, andFIG. 5 is the side elevational view of the oil piping assembly 70 asseen in the leftward direction of FIG. 4. The oil piping assembly 70 isa three-dimensional structure, and the first oil supply passage 42 isaccordingly a three-dimensional passage indicated by broken lines inFIG. 5. Described more specifically, the oil piping assembly 70 includesa first pipe portion 82 having a first passage portion 80, a second pipeportion 86 having a second passage portion 84, and a connecting pipeportion 90 having a connecting passage portion 88 for communicationbetween the first and second passage portions 80 and 84. The firstpassage portion 80 has a limited three-dimensional configuration more orless similar to a two-dimensional configuration, and the second passageportion 84 has a two-dimensional configuration. The second pipe portion86 having the second passage portion 84 has a two-dimensional structurelying in a substantially vertical two-dimensional plane defined by avertical direction and the longitudinal direction of the hybrid vehicle10. The first pipe portion 82 having the first passage portion 80 has alimited three-dimensional structure including a curved intermediate partwhich protrudes from a two-dimensional plane parallel to thetwo-dimensional plane of the second pipe portion 86, in the width ortransverse direction of the hybrid vehicle 10. The curved intermediatepart includes inclined sections having inclination angles not largerthan 45°. The connecting pipe portion 90 having the connecting passageportion 88 extends substantially linearly in the width direction of thehybrid vehicle 10 and in a substantially horizontal direction, and isconnected to the first and second pipe portions 82 and 86, so as tointersect at right angles these pipe portions 82 and 86 respectively. Asshown in FIG. 4, the first and second pipe portions 82 and 86 extendfrom the connecting pipe portion 90 in the respective opposite verticaldirections (downward and upward directions). The plurality of hollownozzle portions 76 of the second pipe portion 86 extend linearly in thehorizontal direction (width direction of the hybrid vehicle 10) parallelwith the connecting pipe portion 90, and have respective deliverynozzles 78 formed at their end parts such that the delivery nozzles 78are open externally of the nozzle portions 76, more specifically, opendownwards in the present embodiment. The first pipe portion 82 has acylindrical connector port 92 formed at an end part of the first pipeportion 82 remote from the connecting pipe portion 90 such that theconnector port 92 extends linearly in the horizontal direction (widthdirection of the hybrid vehicle 10) parallel with the connecting pipeportion 90.

The above-described oil piping assembly 70 includes a plurality ofdivisional components corresponding two of which cooperate to define acircumference of the first oil supply passage 42 along a length of thefirst oil supply passage 42. Each divisional component is made of resinmaterial. As shown in FIG. 6, the oil piping assembly 70 according tothe present embodiment consists of three divisional components, that is,a base divisional component 100, a first divisional component 102 and asecond divisional component 104. The base divisional component 100consists of a pair of half components, that is, a first half component114 and a second half component 116 which have respective first andsecond A-grooves 110 and 112 which are open in respective oppositedirections. The first and second half components 114 and 116 also haverespective interfacial surfaces 114 f and 116 f. The first A-groove 110is open in the direction of the interfacial surface 114 f, i.e., thenormal direction of the interfacial surface 114 f or a directionperpendicular to the interfacial surface 114 f, namely, open in theleftward direction as seen in FIG. 5, and the second A-groove 112 isopen in the direction perpendicular to the interfacial surface 116 f,namely, open in the rightward direction as seen in FIG. 5. That is, thefirst and second A-grooves 110 and 112 are open in the respectiveopposite directions parallel to the width direction of the hybridvehicle 10, and the first and second half components 114 and 116 areoffset or spaced apart from each other in the width direction of thehybrid vehicle 10. Described more specifically, the first half component114 is offset or spaced apart from the second half component 116 in therightward direction parallel to the width direction of the hybridvehicle 10, as seen in FIG. 6, while the second A-groove 112 formed inthe second half component 116 is open in the leftward direction. Thefirst and second half components 114 and 116 are connected to each otherat their respective upper and lower end portions, by the connecting pipeportion 90 extending in the width direction of the hybrid vehicle 10,such that the first and second half components 114 and 116 extend fromthe connecting pipe portion 90 in the respective vertically oppositedirections, that is, in the downward and upward directions. Theconnecting passage portion 88 formed through the connecting pipe portion90 is open in bottom walls of the first and second A-grooves 110 and112. Further, the connector port 92 extends integrally from the lowerend portion of the first half component 114, linearly parallel with theconnecting pipe portion 90, in the direction opposite to the directionin which the first A-groove 110 is open, while the nozzle portions 76extend integrally from the second half component 116, linearly parallelwith the connecting pipe portion 90, in the direction opposite to thedirection in which the second A-groove 112 is open. Hatching lines inFIG. 6 around the first A-groove 110 represent the interfacial surface114 f, for easier recognition of the interfacial surface 114 f.

FIG. 8 is the cross sectional view of a molding device 130 forintegrally forming the base divisional component 100 by an injectionmolding process. The molding device 130 has a molding portion 132 forforming the connector port 92, a molding portion 134 for forming theconnecting pipe portion 90, and molding portions 136 for forming theplurality of nozzle portions 76. These molding portions 132, 134 and136, which are parallel to each other, lie in one plane. The moldingdevice 130 principally consists of a lower stationary mold 138 and anupper movable mold 140. The movable mold 140 is movable upwards anddownwards away from and toward the stationary mold 138. That is, thedirection in which the movable mold 140 is vertically movable (as seenin FIG. 8) is parallel to a direction of extension of the mutuallyparallel connecting pipe portion 90, nozzle portions 76 and connectorport 92, and is parallel to the direction in which the first and secondA-grooves 110 and 112 are open, which direction is perpendicular to theinterfacial surfaces 114 f and 116 f. When the molding device 130 isplaced in a closed state with the movable mold 140 being moved downwardsas seen in FIG. 8, a mold cavity 142 having the molding portions 132,134 and 136 is formed within the thus closed molding device 130. Amolten resin material is injected into the mold cavity 142, and is thencooled and cured. As a result, the base divisional component 100 havingthe first and second A-grooves 110 and 112 is formed within the moldcavity 142, integrally with the connecting pipe portion 90 having theconnecting passage portion 88, the hollow nozzle portions 76, thecylindrical connector port 92. The base divisional component 100 may besubjected to a machining operation for its intricate shaping adjustment,as needed. For instance, the connecting pipe portion 90 may be subjectedto a machining operation on an outer circumferential surface, to removeunnecessary stock or burrs. For instance, each of the delivery nozzles78 of the nozzle portions 76 may be formed by the injection moldingprocess to form the base divisional component 100, with a movement of aslidable mold (not shown in FIG. 8) which is incorporated within themovable mold 140 and which is movable by a cam, in the leftward andrightward directions as seen in FIG. 8, in synchronization of themovement of the movable mold 140. However, the delivery nozzles 78 maybe formed by a machining operation, for example, after the injectionmolding process. While the fixing portions 72 are formed integrally withthe base divisional component 100 by the injection molding process,reinforcing metallic plates are embedded in the fixing portions 72 asneeded, by an insert-forming process.

Referring back to FIG. 6, the first divisional component 102 has a firstB-groove 118 and cooperates with the first half component 114 of thebase divisional component 100, to define therebetween the first passageportion 80. The first divisional component 102 has an interfacialsurface 102 f around an opening of the first B-groove 118. The firstdivisional component 102 is bonded to the first half component 114 suchthat the interfacial surface 102 f is held in abutting contact with theinterfacial surface 114 f around an opening of the first A-groove 110.Thus, the first passage portion 80 is defined by the first A-groove 110and the first B-groove 118. The first B-groove 118 is open in thedirection perpendicular to the interfacial surface 102 f of the firstdivisional component 102, namely, open in the rightward direction asseen in FIG. 5, so that the interfacial surface 114 f of the first halfcomponent 114 and the interfacial surface 102 f of the first divisionalcomponent 102 are fluid-tightly abuttable with each other. It is notedthat the interfacial surface 102 f is a third interfacial surface, whilethe interfacial surface 114 f is a first interfacial surface which hasrecesses and protrusions for fluid-tight contact with respectiveprotrusions and recesses of the third interfacial surface.

FIG. 9 is the cross sectional view of a molding device 150 forintegrally forming the first divisional component 102 by an injectionmolding process. The molding device 150 principally consists of a lowerstationary mold 152 and an upper movable mold 154. The movable mold 154is movable upwards and downwards away from and toward the stationarymold 152. That is, the direction in which the movable mold 154 isvertically movable (as seen in FIG. 9) is parallel to the direction inwhich the first B-groove 118 is open, which direction is perpendicularto the interfacial surface 102 f. When the molding device 150 is placedin a closed state with the movable mold 154 being moved downwards asseen in FIG. 9, a mold cavity 156 corresponding to the first divisionalcomponent 102 is formed within the thus closed molding device 150. Amolten resin material is injected into the mold cavity 156, and is thencooled and cured. As a result, the first divisional component 102 havingthe first B-groove 118 is integrally formed within the mold cavity 156.The first divisional component 102 may be subjected to a machiningoperation for its intricate shaping adjustment, as needed.

The second divisional component 104 has a second B-groove 120 andcooperates with the second half component 116 of the base divisionalcomponent 100, to define therebetween the second passage portion 84. Thesecond divisional component 104 has an interfacial surface 104 f aroundan opening of the second B-groove 120. The second divisional component104 is bonded to the second half component 116 such that the interfacialsurface 104 f is held in abutting contact with the interfacial surface116 f around an opening of the second A-groove 112. Thus, the secondpassage portion 84 is defined by the second A-groove 112 and the secondB-groove 120. The second B-groove 120 is open in the directionperpendicular to the interfacial surface 104 f of the second divisionalcomponent 104, namely, open in the leftward direction as seen in FIG. 5,so that the interfacial surface 116 f of the second half component 116and the interfacial surface 104 f of the second divisional component 104are fluid-tightly abuttable with each other. It is noted that theinterfacial surface 104 f is a fourth interfacial surface, while theinterfacial surface 116 f is a second interfacial surface which hasrecesses and protrusions for fluid-tight contact with respectiveprotrusions and recesses of the fourth interfacial surface. As shown inFIG. 5, the second divisional component 104 has the plurality ofintegrally formed hollow nozzle portions 76 linearly extending in thewidth direction of the hybrid vehicle 10, more specifically, in thedirection opposite to the direction in which the second B-groove 120 isopen. Hatching lines in FIG. 6 around the second B-groove 120 representthe interfacial surface 104 f, for easier recognition of the interfacialsurface 104 f.

FIG. 10 is the cross sectional view of a molding device 160 forintegrally forming the second divisional component 104 by an injectionmolding process. The molding device 160 has a molding portion 162 forforming the plurality of mutually parallel nozzle portions 76. Themolding device 160 principally consists of a lower stationary mold 164and an upper movable mold 166. The movable mold 166 is movable upwardsand downwards away from and toward the stationary mold 164. That is, thedirection in which the movable mold 166 is vertically movable (as seenin FIG. 10) is parallel to the direction of extension of the nozzleportions 76 and to the direction in which the second B-groove 120 isopen, which direction is perpendicular to the interfacial surface 104 f.When the molding device 160 is placed in a closed state with the movablemold 166 being moved downwards as seen in FIG. 10, a mold cavity 168having the molding portion 162 is formed within the thus closed moldingdevice 160. A molten resin material is injected into the mold cavity168, and is then cooled and cured. As a result, the second divisionalcomponent 104 having the nozzle portions 76 and the second B-groove 120is integrally formed within the mold cavity 168. The second divisionalcomponent 104 may be subjected to a machining operation for itsintricate shaping adjustment, as needed. For instance, each of thedelivery nozzles 78 of the nozzle portions 76 may be formed by theinjection molding process to form the second divisional component 104,with a movement of a slidable mold (not shown in FIG. 10) which isincorporated within the movable mold 166 and which is movable by a cam,in the leftward and rightward directions as seen in FIG. 10, insynchronization of the movement of the movable mold 166. However, thedelivery nozzles 78 may be formed by a machining operation, for example,after the injection molding process.

Then, the first and second divisional components 102 and 104 areintegrally bonded to the respective first and second half components 114and 116 of the base divisional component 100, by a vibration weldingprocess. Namely, the first divisional component 102 and the first halfcomponent 114 are pressed in the respective leftward and rightwarddirections as seen in FIG. 5, for pressing fluid-tight contact of theinterfacial surfaces 102 f and 114 f with each other in the directionsubstantially perpendicular to these surfaces 102 f and 114 f, while thecomponents 102 and 114 are vibrated in the directions perpendicular tothe plane of the view of FIG. 5 such that the interfacial surfaces 102 fand 114 f are kept in pressing sliding contact with each other, wherebythese surfaces 102 f and 114 f are welded together due to friction heat.As a result, the first pipe portion 82 having the first passage portion80 is obtained. FIG. 7 is the schematic cross sectional view of thefirst pipe portion 82 taken in a direction indicated by lines VII-VII inFIG. 4. The first divisional component 102 and the first half component114 are bonded together with their interfacial surfaces 102 f and 114 fbeing held in contact with each other. Further, the thus bondedcomponents 102 and 114 have two flanges, as needed, which flanges extendradially outwardly from their respective two circumferential positionsat which the interfacial surfaces 102 f and 114 f are held in contactwith each other.

Similarly, the second divisional component 104 and the second halfcomponent 116 are pressed in the respective leftward and rightwarddirections as seen in FIG. 5, for pressing fluid-tight contact of theinterfacial surfaces 104 f and 116 f with each other in the directionsubstantially perpendicular to these surfaces 104 f and 116 f, while thecomponents 104 and 116 are vibrated in the directions perpendicular tothe plane of the view of FIG. 5, or in the upward and downwarddirections, such that the interfacial surfaces 104 f and 116 f are keptin pressing sliding contact with each other, whereby these surfaces 104f and 116 f are welded together due to friction heat. As a result, thesecond pipe portion 86 having the second passage portion 84 is obtained.The thus obtained second pipe portion 86 is connected to the first pipeportion 82, whereby the desired oil piping assembly 70 is manufactured.The thus bonded components 104 and 116 also have two flanges (notshown), as needed, which flanges extend radially outwardly from theirrespective two circumferential positions at which the interfacialsurfaces 104 f and 116 f are held in contact with each other. In thevibration welding process to weld the first and second divisionalcomponents 102 and 104 to the respective first and second halfcomponents 114 and 116 of the base divisional component 100, theinterfacial surfaces 102 f, 104 f, 114 f and 116 f may be heated byexposure to infrared rays, as needed, before the vibration weldingoperation is performed together with the pressing operation.

It is noted that the injection molding process to integrally form eachof the base divisional component 100, the first divisional component 102and the second divisional component 104 by using the respective moldingdevices 130, 150 and 160 shown in FIGS. 8 to 10 respectively is aforming step of the process of forming the oil piping assembly 70according to the present embodiment of this invention. It is furthernoted that the vibration welding process to bond the first divisionalcomponent 102 to the first half component 114 of the base divisionalcomponent 100 is a first bonding step of the above-indicated process offorming the oil piping assembly 70, while the vibration welding processto bond the second divisional component 104 to the second half component116 of the base divisional component 100 is a second bonding step of theabove-indicated process of forming the oil piping assembly 70. The firstand second bonding steps may be implemented in this order ofdescription, or vice versa.

As described above, the resin piping assembly 70 according to thepresent embodiment of the invention comprises the base divisionalcomponent 100 including the first and second half components 114 and 116connected to each other through the connecting pipe portion 90, and thefirst and second divisional components 102 and 104 cooperating with therespective first and second half components 114 and 116 to form therespective first and second passage portions 80 and 84 of the oilpassage 42. For bonding the first and second divisional components 102and 104 to the respective first and second half components 114 and 116in the vibration welding process by pressing contact of the first andthird interfacial surfaces 114 f and 102 f with each other, and bypressing contact of the second and fourth interfacial surfaces 116 f and104 f with each other, each of those first through fourth interfacialsurfaces 114 f, 116 f, 102 f and 104 f is required to have atwo-dimensional configuration or a limited three-dimensionalconfiguration, so that a desired pressing force can be applied to anentire area of each of the interfacial surfaces 114 f, 116 f, 102 f and104 f. Accordingly, each of the first and second passage portions 80 and84 is also required to have a two-dimensional configuration or a limitedthree-dimensional configuration. In the oil piping assembly 70 accordingto the present embodiment, however, the configurations of the first andsecond passage portions 80 and 84 can be designed independently of eachother, so as to permit application of the desired pressing force to theentire area of each interfacial surface 114 f, 116 f, 102 f, 104 f.Further, the first and second passage portions 80 and 84 are spacedapart from each other and are held in communication with each otherthrough the connecting pipe portion 90, so that the oil piping assembly70 has a high degree of freedom of design of configuration of the oilpassage 42 including the connecting passage portion 88 of the connectingpipe portion 90. Accordingly, the present oil piping assembly 70 can beformed to have a comparatively complicated three-dimensionalconfiguration while ensuring a high degree of bonding of the first andsecond divisional components 102 and 104 to the first and second halfcomponents 114 and 116 of the base divisional component 100.

The present embodiment is further configured such that the connectingpipe portion 90 having the connecting passage portion 88 forcommunication between the first and second passage portions 84 and 88 isa completely cylindrical body a diameter, a wall thickness and otherspecifications of which can be suitably and easily determined so as tohave a required strength. This cylindrical connecting pipe portion 90having the required strength cooperates with the first and seconddivisional components 102 and 104 having a sufficient strength of theirmutual bonding, to permit the resin piping assembly 70 to have a highdegree of freedom of design of configuration of the first oil supplypassage 42 as well as a high degree of strength.

The present embodiment is also configured such that the connecting pipeportion 90 linearly extends along a straight line (in the widthdirection of the hybrid vehicle 10), and the first and second A-grooves110 and 112 of the first and second interfacial surfaces 114 f and 116 fof the first and second half components 114 and 116 of the basedivisional component 100 are open in respective opposite directionsparallel to the straight line. Further, the first and second halfcomponents 114 and 116 are spaced apart from (offset with respect to)each other in the direction parallel to the straight line, and areconnected at their ends to each other through the connecting pipeportion 90, such that the first and second half components 114 and 116extend from the connecting pipe portion 90 in respective oppositedirections perpendicular to the straight line. Accordingly, the basedivisional component 100 including the first and second half components114 and 116 and the connecting pipe portion 90 can be formed as aone-piece body with the first and second interfacial surfaces 114 f and116 f having the respective A-grooves 110 and 112, by an injectionmolding process by using the molding device 130 provided with thestationary mold 138 and the movable mold 140 which are movable relativeto each other in the direction parallel to the above-indicated straightline. Thus, the base divisional component 100 can be easily andeconomically formed. The molding device 130 need not be provided with asliding mold movable in a direction perpendicular to the straight line,and may principally consist of the stationary and movable molds 138 and140, so that the molding device 130 has a comparatively simplestructure, which can be manufactured at a low cost.

The present embodiment is further configured such that the second halfcomponent 116 of the base divisional component 100 and the seconddivisional component 104 are provided with the integrally formed hollownozzle portions 76 extending in the direction opposite to the directionsin which the grooves 112 and 120 of the second and fourth interfacialsurfaces 116 f and 104 f are open. The hollow nozzle portions 76 permitextension of the first oil supply passage 42, without reducing thestrength of bonding of the second divisional component 104 to the secondhalf component 116 of the base divisional component 100. Further, thehollow nozzle portions 76 formed integrally with the base divisionalcomponent 100 and the second divisional component 104 permit economicalmanufacture of the oil piping assembly 70 with a reduced number ofparts, than where separately formed nozzles are fixed to a resin pipingassembly with screws or any other fastening members.

The present embodiment is also configured such that the cylindricalconnecting pipe portion 90 linearly extends along a straight line, andthe second half component 116 of the base divisional component 100 isprovided with the hollow nozzle portions 76 such that the hollow nozzleportions 76 linearly extend along a straight line parallel to thedirection of extension of the cylindrical connecting pipe portion 90.Accordingly, the base divisional component 100 including the connectingpipe portion 90 and the hollow nozzle portions 76 can be formed as aone-piece body, by an injection molding process or a press-formingprocess, for example, by using the molding device 130 provided with thestationary and movable molds 138 and 140 which are movable toward andaway from each other in the direction parallel to the above-indicatedstraight line. Thus, the base divisional component 100 including thecylindrical connecting pipe portion 90 and the hollow nozzle portions 76can be easily and economically formed.

The present embodiment is further configured such that the first halfcomponent 114 of the base divisional component 100 is provided, at itsend remote from the second half component 116, with the integrallyformed cylindrical connector port 92 such that the cylindrical connectorport 92 linearly extend along the straight line parallel to thedirection of extension of the cylindrical connecting pipe portion 90, inthe direction opposite to the direction in which the first A-groove 110formed in the first interfacial surface 114 f is open. Accordingly, thecylindrical connector port 92 can be formed, without reducing thestrength of bonding of the first divisional component 102 to the firsthalf component 114. Further, the cylindrical connector port 92 formedintegrally with the base divisional component 100 permits economicalmanufacture of the resin piping assembly 70 with a reduced number ofparts, than where a separately formed connector port is fixed to a resinpiping assembly with screws or any other fastening members. In addition,since the connector port 92 is formed so as to extend along the straightline parallel to the direction of extension of the connecting pipeportion 90, the base divisional component 100 including the connectorport 92 as well as the connecting pipe portion 90 and the hollow nozzleportions 76 can be formed as a one-piece body, by an injection moldingprocess or a press-forming process, for example, by using the moldingdevice 130 provided with the stationary and movable molds 138 and 140which are movable relative to each other in the direction parallel tothe above-indicated straight line. Thus, the base divisional component100 including the connecting pipe portion 90, the hollow nozzle portions76 and the connector port 92 can be easily and economically formed.

The oil piping assembly 70 is used to deliver the lubricant oil 48 tothe bearings 62 and the gears 64 of the vehicular power transmittingsystem in the form of the transaxle 12. Since the first oil supplypassage 42 has a high degree of freedom of design of its configuration,the oil piping assembly 70 can be compactly disposed in a complicatednarrow space within the casing 14 of the transaxle 12, and can deliverthe lubricant oil 48 exactly to the bearings 62 and the gears 64 in apin-pointing manner, so that a required volume of the lubricant oil 48can be reduced.

According to the present embodiment, after the base divisional component100, and the first and second divisional components 102 and 104 areformed by the injection molding process, the first half component 114 ofthe base divisional component 100 and the first divisional component 102are bonded together with their limited three-dimensional first and thirdinterfacial surfaces 114 f and 102 f being held in pressing contact witheach other, while the second half component 116 of the base divisionalcomponent 100 and the second divisional component 104 are bondedtogether with their two-dimensional second and fourth interfacialsurfaces 116 f and 104 f being held in pressing contact with each other.Accordingly, the resin piping assembly 70 having a high degree ofstrength of bonding of the first and second divisional components 102and 104 to the base divisional component 100 can be easily andeconomically manufactured, with a high degree of freedom of design ofconfiguration of the first oil supply passage 42.

Further, the vibration welding process is implemented to bond the firstand second divisional components 102 and 104 to the respective first andsecond half components 114 and 116 of the base divisional component 100.To ensure a desired strength of bonding of the divisional components 102and 104 to the half components 114 and 116, the desired pressing forceis required to be applied to the entire areas of the first and thirdinterfacial surfaces 114 f and 102 f, and the entire areas of the secondand fourth interfacial surfaces 116 f and 104 f. In this respect, it isnoted that the first through fourth interfacial surfaces 114 f, 116 f,102 f and 104 f have the limited three-dimensional or two-dimensionalconfigurations, like the first and second passage portions 80 and 84, sothat the first and second divisional components 102 and 104 can beadequately bonded to the respective first and second half components 114and 116 in the vibration welding process, with the required pressingforce being applied to the entire areas of the interfacial surfaces 114f, 116 f, 102 f and 104 f.

Other embodiments of this invention will be described. It is noted thatthe same reference signs as used in the first embodiment will be used toidentify the corresponding elements of the following embodiments, whichwill not be described redundantly.

Referring next to FIG. 11 which is the side elevational viewcorresponding to that of FIG. 5, showing an oil piping assembly 200according to a second embodiment of this invention, which is formed of aresin material. A front elevational view of the oil piping assembly 200is similar to that of FIG. 4. In this oil piping assembly 200, the firstpipe portion 82, the second pipe portion 86, the first passage portion80 formed through the first pipe portion 82, and the second passageportion 84 formed through the second pipe portion 86 havetwo-dimensional configurations as seen in two-dimensional planes whichare perpendicular to a plane of the view of FIG. 11 and each of which isdefined by the vertical and longitudinal directions of the hybridvehicle 10. The oil piping assembly 200 includes the base divisionalcomponent 100 having the first and second interfacial surfaces 114 f and116 f, the first divisional component 102 having the third interfacialsurface 102 f, and the second divisional component 104 having the fourthinterfacial surface 104 f. The first to fourth interfacial surfaces 114f, 102 f, 116 f, 104 f are parallel to the two-dimensional planes. Theoil piping assembly 200 is not provided with hollow nozzle portions.Instead, the second half component 116 or the second divisionalcomponent 104 has delivery nozzles or connector fittings held incommunication with the second passage portion 84, so that the lubricantoil 48 is delivered from the delivery nozzles, or delivered throughexternal oil passages connected to the connector fittings. It is notedthat the connector port 92 shown in FIG. 11 may be dispensed with. Inthis case, the first half component 114 or the first divisionalcomponent 102 has a connector fitting which is held in communicationwith the first passage portion 80 and which is connected to the firstoil pump P1.

In this oil piping assembly 200, too, the first pipe portion 82 and thesecond pipe portion 86 lie in respective two-dimensional planes whichare spaced apart from each other in the width direction of the hybridvehicle 10. Accordingly, the oil piping assembly 200 has substantiallythe same advantages as the oil piping assembly 70, in that the first andsecond divisional components 102 and 104 are bonded to the basedivisional component 100 with a high degree of bonding strength, and inthat the first oil supply passage 42 including the connecting passageportion 88 of the connecting pipe portion 90 has a high degree offreedom of design of its configuration.

Although the first and second half components 114 and 116 of the basedivisional component 100, and the first and second divisional components102 and 104 have the respective first, second, third and fourthinterfacial surfaces 114 f, 116 f, 102 f and 104 f parallel to thetwo-dimensional plane perpendicular to the plane of the view of FIG. 11and parallel to the vertical direction of the hybrid vehicle 10, thoseinterfacial surfaces 114 f, 116 f, 102 f and 104 f need not be parallelto each other. For instance, the second interfacial surface 116 f of thesecond half component 116 of the base divisional component 100, and thefourth interfacial surface 104 f of the second divisional component 104may be parallel to the plane of the view of FIG. 11. Further, the secondpipe portion 86 may be inclined in the width direction of the hybridvehicle 10 as the second pipe portion 86 extends upwards from theconnecting pipe portion 90. Namely, the second interfacial surface 116 fof the second half component 116 bonded to the second divisionalcomponent 104 may be inclined as described above. This modificationapplies to the oil piping assembly 70 according to the first embodiment.

Reference is then made to FIG. 12 which is the side elevational viewcorresponding to that of FIG. 5, showing an oil piping assembly 210according to a third embodiment of this invention, which is also formedof a resin material. A front elevational view of the oil piping assembly210 is similar to that of FIG. 4. This oil piping assembly 210 isidentical with the oil piping assembly 70, regarding the first andsecond divisional components 102 and 104, but is different from the oilpiping assembly 70, regarding a base divisional component 212. Namely,the base divisional component 212 includes the first and second halfcomponents 114 and 116, like the base divisional component 100 in thefirst and second embodiments, and the first and second divisionalcomponents 102 and 104 are bonded to the base divisional component 212,by pressing the base divisional component 212 and the first and seconddivisional components 102 and 104 against each other in the leftward andrightward directions as seen in FIG. 12. However, the oil pipingassembly 210 is different from the oil piping assembly 70, regarding acylindrical connecting pipe portion 216 having a connecting passageportion 214 for communication between the first and second passageportions 80 and 84, a cylindrical connector port 218 provided on thefirst half component 114, and a plurality of hollow nozzle portions 220provided on the second half component 116. The connecting pipe portion216 connecting the first and second half components 114 and 116 linearlyextends along a straight line inclined vertically with respect to thehorizontal direction, in the vertical plane parallel to the widthdirection of the hybrid vehicle 10, as shown in FIG. 12, whilehorizontal direction crosses the first and second half components 114and 116 at a right angle respectively. The connector port 218 and thehollow nozzle portions 220 linearly extend along a straight lineparallel to the direction of extension of the connecting pipe portion216. The hollow nozzle portions 220 have delivery nozzles 222 at theirdistal end portions such that the delivery nozzles 222 are opendownwards.

Like the base divisional component 100, the base divisional component212 can also be formed as a one-piece unit by an injection moldingprocess. FIG. 13 is the cross sectional view corresponding to that ofFIG. 8, showing a molding device 230. The cross sectional view shows amolding portion 232 for forming the connector port 218, a moldingportion 234 for forming the connecting pipe portion 216, and moldingportions 236 for forming the hollow nozzle portions 220. These moldingportions 232, 234 and 236, which are parallel to each other, lie in oneplane. The molding device 230 principally consists of a lower stationarymold 238 and an upper movable mold 240. The movable mold 240 is movableupwards and downwards away from and toward the stationary mold 238. Thatis, the direction in which the movable mold 240 is vertically movable(as seen in FIG. 13) is parallel to a direction of extension of themutually parallel connecting pipe portion 216, connector port 218, andhollow nozzle portions 220. When the molding device 230 is placed in aclosed state with the movable mold 240 being moved downwards as seen inFIG. 13, a mold cavity 242 having the molding portions 232, 234 and 236is formed within the thus closed molding device 230. A molten resinmaterial is injected into the mold cavity 242, and is then cooled andcured. As a result, the base divisional component 212 having the firstand second A-grooves 110 and 112 is formed within the mold cavity 242,integrally with the connecting pipe portion 216 having the connectingpassage portion 214, the cylindrical connector port 218 and the hollownozzle portions 220. The base divisional component 212 may be subjectedto a machining operation for its intricate shaping adjustment, asneeded. For instance, the connecting pipe portion 216 may be subjectedto a machining operation on its outer circumferential surface, to removeunnecessary stock or burrs. For instance, each of the delivery nozzles222 of the nozzle portions 220 may be formed by the injection moldingprocess to form the base divisional component 212, with a movement of aslidable mold, as in the first embodiment. However, the delivery nozzles222 may be formed by a machining operation, for example, after theinjection molding process.

In the present embodiment, the A-grooves 110 and 112 formed in the firstand second interfacial surfaces 114 f and 116 f are open in therespective opposite directions parallel to the direction of extension ofthe connecting pipe portion 216. Although the first and seconddivisional components 102 and 104 may be pressed against the respectivefirst and second half components 114 and 116 in the vibration weldingprocess, in the direction of extension of the connecting pipe portion216, the divisional components 102 and 104 are preferably pressedagainst the respective divisional components 114 and 116, in theleftward and rightward directions as seen in FIG. 12, that is, inopposite directions which are perpendicular or substantiallyperpendicular to the first and second interfacial surfaces 114 f and 116f, as in the first and second embodiments.

While the preferred embodiments of the invention have been described forillustrative purpose only, it is to be understood that the presentinvention may be embodied with various changes and improvements, whichmay occur to those skilled in the art.

NOMENCLATURE OF ELEMENTS

-   12: transaxle (power transmitting system)-   42: first oil supply passage (oil passage)-   48: oil-   62: bearings (lubricated portions)-   64: gears (lubricated portions)-   70, 200, 210: oil piping assembly (resin piping assembly)-   76, 220: nozzle portions-   78, 222: delivery nozzles-   80: first passage portion-   84: second passage portion-   88, 214: connecting passage portion-   90, 216: connecting pipe portion-   92, 218: connector port-   100, 212: base divisional component-   102: first divisional component-   102 f: third interfacial surface-   104: second divisional component-   104 f: fourth interfacial surface-   110: first A-groove (groove)-   112: second A-groove (groove)-   114: first half component-   114 f: first interfacial surface-   116: second half component-   116 f: second interfacial surface-   130, 230: molding device-   138, 238: stationary mold-   140, 240: movable mold

What is claimed is:
 1. A process of forming a resin piping assemblyhaving an oil passage and comprising: a base divisional componentincluding a first half component having a first interfacial surfaceformed along the oil passage, and a second half component having asecond interfacial surface formed along the oil passage; a firstdivisional component having a third interfacial surface formed along theoil passage, and bonded to the first half component with the first andthird interfacial surfaces being held in contact with each other, so asto form a first passage portion of the oil passage; and a seconddivisional component having a fourth interfacial surface formed alongthe oil passage, and bonded to the second half component with the secondand fourth interfacial surfaces being held in contact with each other,so as to form a second passage portion of the oil passage, wherein: eachof the base divisional component, the first divisional component and thesecond divisional component is formed of a resin material, the first andsecond half components are spaced apart from each other along a lengthof the oil passage, and the first and second interfacial surfaces areopen in respective opposite directions, and the base divisionalcomponent further includes a cylindrical connecting pipe portionincluding a cylindrical outer surface and a connecting passage portionwhich is a part of the oil passage and which is provided forcommunication between the first and second passage portions, the processcomprising: forming the base divisional component, the first divisionalcomponent and the second divisional component by an injection moldingprocess, respectively; bonding the first divisional component to thefirst half component of the base divisional component, by pressingcontact of the first interfacial surface of the first half componentwith the third interfacial surface of the first divisional component;and bonding the second divisional component to the second half componentof the base divisional component, by pressing contact of the secondinterfacial surface of the second half component with the fourthinterfacial surface of the second divisional component.
 2. The processaccording to claim 1, wherein the bonding of the first divisionalcomponent to the first half component includes a vibration welding stepin which the first interfacial surface of the first half component andthe third interfacial surface of the first divisional component are heldin pressing sliding contact with each other, and the bonding of thesecond divisional component to the second half component includes avibration welding step in which the second interfacial surface of thesecond half component and the fourth interfacial surface of the seconddivisional component are held in pressing sliding contact with eachother.
 3. The process according to claim 1, wherein: the firstinterfacial surface of the first half component has a groove partiallydefining the first passage portion, and the second interfacial surfaceof the second half component has a groove partially defining the secondpassage portion, the connecting pipe portion linearly extends along astraight line, and the first and second half components are spaced apartfrom each other in a direction parallel to the straight line, thegrooves of the first and second interfacial surfaces are open inrespective opposite directions parallel to the straight line, and thefirst and second half components extend from the connecting pipe portionin respective opposite directions perpendicular to the straight line,and the base divisional component is integrally formed with the firstand second half components having the respective grooves, and theconnecting pipe portion, by the injection molding process, by using amolding device having a pair of forming molds which are movable towardand away from each other in the direction parallel to the straight line.4. The process according to claim 3, wherein: the second half componentof the base divisional component is provided with a plurality of hollownozzle portions each linearly extending in a direction of the straightline and a direction opposite to a direction in which the groove formedin the second interfacial surface is open, each of the hollow nozzleportions having a delivery nozzle which is open externally of the hollownozzle portion, and the base divisional component is integrally formedwith the hollow nozzle portions, by the injection molding process withthe molding device.
 5. The process according to claim 3, wherein: thefirst half component of the base divisional component is provided with acylindrical connector port linearly extending in a direction of thestraight line and a direction opposite to a direction in which thegroove formed in the first interfacial surface is open, and the basedivisional component is integrally formed with the cylindrical connectorport, by the injection molding process with the molding device.